1. Field of the Invention
This invention relates to an apparatus for joining terminals and more particularly relates to a terminal joining apparatus for permanently joining a temporarily assembled unit in which connecting portions of plural terminals are displaced from and stacked on each other.
For example, in the case where electric wires for a ground cable to be used in a wire harness in an automobile are connected to a ground stud bolt mounted on a vehicle body, a terminal connected to each end of a plurality of electric wires is not inserted into the stud bolt individually. A unit in which the respective terminals are joined together is inserted into the stud bolt by one step, thereby enhancing an efficiency of work.
Each of the ground terminals includes an annular connecting portion having a through-hole to be inserted into the stud bolt, and a barrel portion extending from the connecting portion. The ground terminals are stacked on each other with the connecting portions being displaced from each other to form a temporarily assembled unit. The unit is permanently joined by driving the unit in directions perpendicular to the axes of the barrel portions.
2. Description of the Prior Art
In order to facilitate joining ground terminals, an assignee of the present application has proposed an auxiliary device for coupling two ground terminals (Japanese Patent Public Disclosure No. 2000-068022).
In the auxiliary device for coupling disclosed in the reference, the through-hole in each of the ground terminals in a temporarily assembled condition is enlarged by inserting a tapered coupling tool into the through-hole. The ground terminals are stacked on each other so that the through-holes are aligned on the same axis and then joined permanently together. At this time, the barrel portions of the respective ground terminals extend on a single line with the phases in the circumferential direction being coincident with each other.
The auxiliary device described above is very effective for joining two ground terminals. However, in the case of joining more than three ground terminals, they may be incorrectly assembled with the phases of the barrel portions being inverted in the circumferential direction. In this case, the assembled dimensions or some other feature of the assembly of the ground terminals does not meet the designed specification and this causes the assembly not to be able to be mounted on a component.
When there are more than three ground terminals, the above auxiliary device requires dividing the ground terminals into several groups with each having two ground terminals.